By default, don't include a dependency reference to NuGetizer itself

Fixes NuGet/Home#5109

Author: kzu

src/Build/NuGet.Build.Packaging.Tasks/NuGet.Build.Packaging.targets

@@ -282,7 +282,7 @@ Copyright (c) .NET Foundation. All rights reserved.
 				<Kind>None</Kind>
 			</PackageFile>
 
-			<PackageFile Include="@(PackageReference)">
+			<PackageFile Include="@(PackageReference)" Condition="'%(Identity)' != 'NuGet.Build.Packaging'">
 				<Kind>Dependency</Kind>
 			</PackageFile>
 

src/Build/NuGet.Build.Packaging.Tests/Builder.cs

@@ -20,28 +20,18 @@ public static partial class Builder
 	const string ToolsVersion = "14.0";
 #endif
 
-	public static BuildResult Build(string projectOrSolution, string targets, Dictionary<string, string> properties = null, ILogger logger = null)
+	public static BuildResult Build(ProjectInstance project, string targets, Dictionary<string, string> properties = null, ILogger logger = null)
 	{
-		if (!Path.IsPathRooted(projectOrSolution))
-			projectOrSolution = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, projectOrSolution);
-
-		if (!File.Exists(projectOrSolution))
-			throw new FileNotFoundException($"Project or solution to build {projectOrSolution} was not found.", projectOrSolution);
+		properties = properties ?? new Dictionary<string, string>();
 
 		// Without this, builds end up running in process and colliding with each other, 
 		// especially around the current directory used to resolve relative paths in projects.
 		//Environment.SetEnvironmentVariable("MSBUILDNOINPROCNODE", "1", EnvironmentVariableTarget.Process);
 		using (var manager = new BuildManager(Guid.NewGuid().ToString()))
 		{
-			properties = properties ?? new Dictionary<string, string>();
-
-			// If file is not a solution, build up a fake solution configuration so P2P references just work
-			if (Path.GetExtension(projectOrSolution) != ".sln")
-				AddSolutionConfiguration(projectOrSolution, properties);
-
-			var request = new BuildRequestData(projectOrSolution, properties, ToolsVersion, targets.Split(','), null);
+			var request = new BuildRequestData(project, targets.Split(','), null);
 			var parameters = new BuildParameters
-			{
+			{ 
 				GlobalProperties = properties,
 				DisableInProcNode = !Debugger.IsAttached,
 				EnableNodeReuse = false,
@@ -61,6 +51,25 @@ public static BuildResult Build(string projectOrSolution, string targets, Dictio
 		}
 	}
 
+	public static BuildResult Build(string projectOrSolution, string targets, Dictionary<string, string> properties = null, ILogger logger = null)
+	{
+		if (!Path.IsPathRooted(projectOrSolution))
+			projectOrSolution = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, projectOrSolution);
+
+		if (!File.Exists(projectOrSolution))
+			throw new FileNotFoundException($"Project or solution to build {projectOrSolution} was not found.", projectOrSolution);
+
+		properties = properties ?? new Dictionary<string, string>();
+
+		// If file is not a solution, build up a fake solution configuration so P2P references just work
+		if (Path.GetExtension(projectOrSolution) != ".sln")
+			AddSolutionConfiguration(projectOrSolution, properties);
+
+		var projectInstance = new ProjectInstance(projectOrSolution, properties, ToolsVersion);
+
+		return Build(projectInstance, targets, properties, logger);
+	}
+
 	static void AddSolutionConfiguration(string projectFile, Dictionary<string, string> properties)
 	{
 		var collection = new ProjectCollection(properties);

src/Build/NuGet.Build.Packaging.Tests/TargetsTests.cs

@@ -1,11 +1,21 @@
 using System.Collections.Generic;
+using System.IO;
+using System.Reflection;
+using Microsoft.Build.Construction;
 using Microsoft.Build.Evaluation;
+using Microsoft.Build.Execution;
+using Microsoft.Build.Framework;
 using Xunit;
+using Xunit.Abstractions;
 
 namespace NuGet.Build.Packaging
 {
 	public class TargetsTests
 	{
+		ITestOutputHelper output;
+
+		public TargetsTests(ITestOutputHelper output) => this.output = output;
+
 		[Fact]
 		public void IncludeFrameworkReferencesInPackage_defaults_to_false_for_build_primary_output()
 		{
@@ -71,6 +81,31 @@ public void PackOnBuild_defaults_to_true_for_compat_GeneratePackageOnBuild_true(
 			Assert.Equal("true", project.GetPropertyValue("PackOnBuild"));
 		}
 
-		
+		[Fact]
+		public void package_contents_never_includes_nugetizer_package_reference()
+		{
+			var xml = ProjectRootElement.Create(Path.Combine(Directory.GetCurrentDirectory(), MethodBase.GetCurrentMethod().Name));
+			xml.AddImport(@"Scenarios\Scenario.props");
+			xml.AddImport(@"Scenarios\Scenario.targets");
+			xml.AddItemGroup()
+				.AddItem("PackageReference", "NuGet.Build.Packaging", new[] { new KeyValuePair<string, string>("Version", "*") });
+
+			xml.Save();
+
+			var project = new ProjectInstance(xml);
+
+			var result = Builder.Build(project, "GetPackageContents");
+
+			Assert.Equal(BuildResultCode.Success, result.OverallResult);
+			Assert.Equal(TargetResultCode.Success, result["GetPackageContents"].ResultCode);
+
+			var items = result["GetPackageContents"].Items;
+
+			Assert.DoesNotContain(items, item => item.Matches(new
+			{
+				Kind = PackageItemKind.Dependency,
+				Identity = "NuGet.Build.Packaging",
+			}));
+		}
 	}
 }